This invention relates to a technique for manufacturing a semiconductor device and, in particular, to a technique for manufacturing a relatively low cost semiconductor device with improved seal properties in a CSP (Chip Size Package).
This invention is the result of the inventor's own research of which a summary follows.
A CSP is a thin, compact semiconductor device of chip size, and it is often used in printed circuit boards built into portable electronic devices.
The general structure of a CSP comprises a thin film wiring substrate on which are mounted bump electrodes which are external terminals, leads electrically connected to electrode pads of a semiconductor chip, an elastomer (elastic structure) arranged between the semiconductor chip and the thin film wiring substrate and formed in approximately the same size as the thin film wiring substrate, and sealing parts which seal the electrode pads and the leads of the thin film wiring substrate connected to it.
Structures of CSPs studied by the inventors for comparison purposes are described, for example, in "Nikkei Microdevices" Apr. 1, 1997, No. 142, pp. 44-53, published by Nikkei BP Co. on Apr. 1, 1997, and, in particular, the next generation CSP structure (comparison examples) described in FIG. 6, on page 48 thereof. This CSP comprises a semiconductor chip having electrode pads formed on its main surface, bump electrodes which are external terminals arranged over the main surface of the semiconductor chip, and a contour ring outside the semiconductor chip.